1. Field of the Invention
The present invention relates to a miniature telephone answering device utilizing microcassettes and having a single head carriage, together with a cam assembly for positioning the carriage.
2. Description of the Prior Art
An objective of the present invention is to provide a telephone answering device which is small enough (typically 130 mm by 65 mm) to be placed beneath a telephone instrument. To accomplish such small size requires the use of microcassettes to record both the outgoing announcement and the incoming message. The requisite small size, and the use of microcassettes, introduce certain complications which must be appropriately handled by the device mechanism.
One of these complications is that there is presently no commercially widely available microcassette having an endless loop. In telephone answering devices using standard size tape cassettes, the outgoing announcement advantageously is recorded on such an endless loop. Thus after transmission of the outgoing announcement, the loop has already recirculated to its start position, so that no "rewind" of the announcement tape is required.
However, if the telephone answering device is to use a conventional microcassette for the outgoing announcement, provision must be made to rewind this cassette as part of the answering cycle. Advantageously, this is done at the end of the answering operation, after the incoming message has been recorded, so that there is no time delay between completion of the outgoing announcement transmission and initiation of recording of the incoming message. Accordingly, it is an object of the present invention to facilitate the automatic rewind of an outgoing announcement microcassette.
Because of the desired size limitation, it is advantageous to have the pinch rollers and record/playback heads for both the outgoing announcement and incoming message tape cassettes mounted on the same head carriage. Such an arrangement should minimize the mechanical complexity of the answering device. It is a further object of the present invention to provide such a unitary head carriage.
To utilize such a unitary head carriage requires some mechanism to ensure that in the engaged position, the pinch rollers for both the outgoing and incoming cassettes are firmly in contact with their respective tape drive capstans. If all of the mechanical components of the device, both on the chassis and on the head carriage itself are perfectly symmetric, then uniform contact of the pinch rollers with the capstans normally can be achieved by direct forward translation of the unitary head carriage from a retracted to an engaged position. However, typical manufacturing variations can be expected to result in some asymmetry of component placement. Therefore, provision must be made to permit sufficient lateral play in the head carriage so that affirmative contact between both pinch rollers and their associated capstans can be ensured when the head carriage is engaged.
On the other hand, such lateral play is undesirable when the head carriage is retracted. In that condition, lateral play could result in a situation where one or the other of the pinch rollers or heads interferes with free tape movement during a rewind or fast forward operation. Thus a further object of the present invention is to provide a head carriage arrangement that permits lateral play in the engaged position but prohibits such lateral play when retracted.
Yet another objective is to provide a drive control mechanism that is useful for both local and remote controlled telephone answering device operation. Local operation requires normal forward and rewind of both the outgoing announcement and incoming message microcassettes. In addition, remote controlled playback of previously recorded incoming messages also requires a fast forward of the incoming tape. Thus five separate tape drive modes must be implemented. A further object of the present invention is to implement these five tape drive operations in a telephone answering device of small size and utilizing microcassettes.